The present invention relates to an image forming apparatus which forms an image by placing image information on a transfer material by using electrophotographic technology.
A conventional method of manufacturing an image forming apparatus will be described in the following. In FIG. 8 and FIG. 9 is shown a conventional method of manufacturing an image forming apparatus, and FIG. 10 is an illustrative diagram showing a state of contact between a photoreceptor unit and a developing roller in a conventional method of manufacturing an image forming apparatus.
FIG. 8, FIG.9 and FIG. 10 show a method of manufacturing an image forming apparatus in a single component developing system using a non-magnetic toner. Firstly, a process unit 1 is described. The process unit 1 comprises a photoreceptor unit 2 and a developing unit 3. The process unit 1 is the control center of the image forming apparatus.
In FIG. 8, the photoreceptor unit 2 comprises a photoreceptor 4, a charged roller 5, a cleaning blade 6, and a discharge lamp 7. The photoreceptor 4 has a surface coated with a layer of organic photoconductive material. The charged roller 5, cleaning blade 6 and discharge lamp 7 are disposed around the photoreceptor 4.
In FIG. 8, the developing unit 3 includes a developing roller 8 and a toner box 9. The toner box 9 has a function to feed a toner 10 to the developing roller 8. A stirring member 11 is fitted to the toner box 9. The stirring member 11 serves to stir the toner 10. The toner 10 is non-magnetic.
In the first place, as shown in FIG. 8, the photoreceptor unit 2 is assembled, followed by the developing unit 3. Secondly, a pin 12 is inserted into a pin hole 2a of the photoreceptor unit 2 and a pin hole 3a of the developing unit 3, thereby combining the photoreceptor unit 2 and developing unit 3 with each other. Further, as shown in FIG. 9, a spring 13 is hooked over a projection 2b of the photoreceptor unit 2 and a projection 3b of the developing unit 3. The photoreceptor unit 2 and developing unit 3 are pulled to each other by the tensile force of the spring 13, thereby causing the photoreceptor 4 and developing roller 8 to come in contact with each other. The toner 10 is filled into the toner box 9 of the developing unit 3. In this way, the process unit 1 of a conventional image forming apparatus has been manufactured.
The mechanism of the process unit 1 will be briefly described in the following with reference to FIG. 9. When the photoreceptor 4 is rotated clockwise, the area coming in contact with the charged roller 5 will be uniformly charged with approximately xe2x88x92600V. Next, when a laser beam as shown by arrow 50 is applied by an exposure means (not shown) to the surface of photoreceptor 4, the electric potential of the area exposed to the laser beam will be increased to approximately xe2x88x92100v. An electrostatic latent image having such different potentials is formed on the surface of photoreceptor 4. When negatively charged toner 10 is pressed against the electrostatic latent image by the developing roller 8, the toner electrostatically sticks to the photoreceptor 4, then the toner image is visualized and appears on the photoreceptor 4 one after another. The toner image is transferred by a transfer means (not shown) onto printing paper (not shown). After that, the toner remaining on the surface of photoreceptor 4 is removed by the cleaning blade 6, thereby physically cleaning the surface of photoreceptor 4. Also, the residual charge of the surface of photoreceptor 4 is eliminated by the discharge lamp 7, thereby electrically cleaning the surface of photoreceptor 4. These processes are repeated before going to the next image forming process.
In such conventional method of manufacturing an image forming apparatus, as shown in FIG. 10, when the developing unit 3 is combined with the photoreceptor unit 2, the surface of photoreceptor 4 comes into direct contact with the surface of developing roller 8. Accordingly, when the image forming apparatus is operated in the functional test before delivery of the product, a rubber portion 8a of developing roller 8 comes into direct contact with the surface of photoreceptor 4. As a result, the rubber portion 8a of developing roller 8 rubs against the surface of photoreceptor 4. This may cause generation of scratches 14 on the surface of photoreceptor 4 during only one turn of rotation before the toner 10 sticks to the developing roller 8. In case scratches 14 are generated on the surface of photoreceptor 4, the electrostatic sensitivity of the area of scratches 14 will be lowered, and consequently, the toner 10 will become hard to stick to the scratched area of the photoreceptor. Excessive scratches will cause generation of defective products. As a result, it will lead to lowering of the product yield and the manufacturing efficiency.
A method of manufacturing an image forming apparatus of the present invention comprises the steps of:
(a) forming a photoreceptor unit having a photoreceptor;
(b) forming a developing unit having a developing roller and a toner;
(c) applying the toner to the surface of the developing roller; and
(d) setting up a combination of the developing unit having the developing roller with the toner applied and the photoreceptor unit.
Preferably, the step of setting up a combination of the developing unit and the photoreceptor unit mentioned includes a process of establishing contact between the developing roller with the toner applied to the surface and the photoreceptor to set up a combination of the photoreceptor unit and the developing unit.
Preferably, the method further comprises a step of
(e) operating an assembled image forming apparatus to perform functional tests of the image forming apparatus.
In the above configuration, there exists a toner between the photoreceptor surface and the developing unit surface. Accordingly, when the photoreceptor unit and the developing unit are combined with each other, the surface of developing roller itself does not come into direct contact with the surface of photoreceptor. The toner existing between the photoreceptor surface and the developing unit surface serves to function as a lubricant. In this way, generation of scratches on the surface of the photoreceptor, due to the developing roller itself, may be prevented. As a result, an excellent image will be formed. It gives rise to the improvement of the manufacturing efficiency of the image forming apparatus.